GATE DA 2025 Q57: Candidate keys and BCNF for R(ABCDEFG)

Consider a database relation R with attributes ABCDEFG, and having the following functional dependencies:

$A \rightarrow BCEF \qquad E \rightarrow DG \qquad BC \rightarrow A$

Which of the following statements is/are correct?

Try it: multiple select: one or more correct options

Select all correct options. No negative marking, no partial marks.

Show answer and explanation

Answer: B, D (official GATE 2025 final answer key)

Concept used: Attribute closure to find candidate keys; BCNF requires every determinant to be a superkey.

First step: Compute closures: $A^+ = ABCEF \cup DG$ = all attributes, and $(BC)^+$ includes A, so it is everything too. Then check $E^+ = EDG$ .

Full step-by-step solution

Detailed working, common mistakes and linked mock tests will be available with a free GATEiit account. Log-in is coming soon.

Share this question

Source: official GATE 2025 DA question paper and final answer key, organised by IIT Roorkee. Question paper · Answer key